Accordion maneuver with a bone fixation device

Abstract

A control system for use with an adjustable bone fixation device including a first fixation element and a second fixation element connectable to bone tissue portions on either side of a treatment site, the control system including: one or more actuators configured to controllably adjust lengths of a plurality of adjustable length struts of the bone fixation device, the plurality of adjustable length struts connecting the first and the second fixation elements of the bone fixation device, length adjustment thereof changing a spatial relationship between the first and the second fixation elements; and circuitry configured to control the one or more actuators to cause the first and second fixation elements to perform an accordion maneuver by performing a plurality of actuations to adjust lengths of the plurality of adjustable length struts to create a reciprocal movement of the first and second fixation elements relative to each other.

1 . A control system for use with an adjustable bone fixation device including a first fixation element and a second fixation element connectable to bone tissue portions either side of a treatment site, the control system comprising:
 one or more actuators configured to controllably adjust lengths of a plurality of adjustable length struts of the bone fixation device, the plurality of adjustable lengths struts connecting said first and said second fixation elements of the bone fixation device, wherein length adjustment thereof changes a spatial relationship between said first and said second fixation elements; and   circuitry configured to control said one or more actuators to cause said first and second fixation elements to perform an accordion maneuver by performing a plurality of actuations to adjust lengths of said plurality of adjustable length struts to create a reciprocal movement of said first and second fixation elements relative to each other.   
     
     
         2 . The control system according to  claim 1 , wherein said one or more actuators comprise a plurality of actuators, each actuator of said plurality of actuators configured to controllably adjust a length of a strut of said plurality of adjustable length struts. 
     
     
         3 . The control system according to  claim 2 , wherein said circuitry is configured to create said reciprocal movement by controlling at least two actuators of said plurality of actuators to simultaneously adjust the length of at least two associated struts to move said first and said second fixation elements relative to each other. 
     
     
         4 . The control system according to  claim 3 , wherein said reciprocal movement of said first and second fixation elements is configured to provide a reciprocal movement to said bone tissue portions. 
     
     
         5 . The control system according to  claim 1 , wherein said circuitry is configured to:
 receive a model including spatial relationships between at least said bone tissue portions, said plurality of adjustable length struts, and said first and said second fixation elements; and   control said plurality of actuations to provide said reciprocal movement to said bone tissue portions, based on said spatial relationships.   
     
     
         6 . The control system according to  claim 5 , wherein said first fixation element is configured to be anchored to bone tissue by at least two first rigid connectors extending from the fixation element into bone tissue, where said first fixation element and said at least two first rigid connectors are sized and shaped, and connection between said first fixation element and said at least two rigid connectors is such that said rigid first connectors extend into said bone tissue from different approach angles;
 wherein said spatial relationships include a spatial relationships between said at least two first rigid connectors, said bone tissue, said plurality of adjustable length struts, and said first and said second fixation elements.   
     
     
         7 . The control system according to  claim 6 , wherein said reciprocal movement comprises oscillating movement of said first and second fixation elements relative to each other. 
     
     
         8 . The control system according to  claim 6 , wherein said plurality of actuations includes a repeating pattern of strut actuations, where repetition is at a frequency of 1-3 Hz to mimic physiological forces experienced by bone tissue during walking. 
     
     
         9 . The control system according to  claim 6 , wherein said plurality of actuations are such that said spatial relationship between said first and second fixation elements is the same prior to said plurality of actuations and after said plurality of actuations, which plurality of actuations maintaining said bone tissue in an initial position. 
     
     
         10 . The control system according to  claim 1 ,
 wherein at least one of said plurality of actuations adjusts said spatial relationship to apply tensile force to bone tissue at a treatment site,   wherein at least one of said plurality of actuations adjusts said spatial relationship to apply compressive force to said bone tissue at said treatment site.   
     
     
         11 . The control system according to  claim 1 , wherein said control system comprises one or more sensors configured to generate one or more sensor signals comprising one or more of:
 a first sensor signal indicative of an axial force applied by one or more adjustable length struts of said plurality of adjustable length struts during one more of said plurality of actuations or bone positioning actuations; and   a second sensor signal of said one or more sensor signals is indicative of a change in dimension of one or more adjustable length struts of said plurality of adjustable length struts during one or more of said plurality of actuations or said bone positioning actuations.   
     
     
         12 . The control system according to  claim 11 , wherein said circuitry is configured to one or more of:
 control one or more of said plurality of actuations or said bone positioning actuations based on said one or more sensor signals; or   determine one or more tissue features, based on said one or more sensor signals.   
     
     
         13 . The control system according to  claim 12 , wherein said tissue features comprise whether bone movement has occurred during an actuation. 
     
     
         14 . The control system according to  claim 12 , wherein said circuitry is configured to perform one or more of said plurality of actuations until said one or more sensor signals produced by said one or more sensors reaches a threshold value. 
     
     
         15 . The control system according to  claim 12 , wherein said circuitry is configured to determine, from said one or more sensor signals:
 an amplitude of said strut dimension adjustment; and   a speed of adjustment of said strut dimension.   
     
     
         16 . An adjustable bone fixation device comprising:
 a first fixation element;   a second fixation element;   a plurality of adjustable length struts; and   a control system comprising:
 one or more actuators configured to controllably adjust lengths of a plurality of adjustable length struts of the bone fixation device, the plurality of adjustable length struts connecting said first and said second fixation elements of the bone fixation device, wherein length adjustment thereof changes a spatial relationship between said first and said second fixation elements; and 
 circuitry configured to control said one or more actuators to cause said first and second fixation elements to perform an accordion maneuver by performing a plurality of actuations to adjust the lengths of said adjustable length struts to create a reciprocal movement of said first and second fixation elements relative to each other; 
   wherein planes of said first and said second fixation elements are orientated generally orthogonally to a central longitudinal axis of said bone tissue; and   wherein said first and said second fixation elements are sized and shaped to externally surround at least a third of a cross sectional circumference of said bone tissue, said cross section taken perpendicular to said central longitudinal axis.   
     
     
         17 . A method of treatment comprising:
 connecting a first fixation element and a second fixation element of an adjustable bone fixation device to different portions of bone tissue, on either side of a treatment site, the first and second fixation elements connected by a plurality of adjustable length rigid struts, adjustable by actuation of one or more actuators; and   automatically actuating said one or more actuators a plurality of times to reciprocally adjust lengths of said plurality of adjustable length rigid struts to perform an accordion maneuver where said first and said second fixation elements move reciprocally relative to each other.   
     
     
         18 . The method according to  claim 17 , comprising:
 receiving one or more measurement signals indicative of axial forces applied by said plurality of adjustable length rigid struts, during said automatically actuating; and   determining one or more tissue parameter, based on said one or more measurement signals.   
     
     
         19 . The method according to  claim 18 , wherein said determining comprises:
 receiving a three-dimensional (3D) model depicting spatial relationships between said different portions of bone tissue and one or more portions of the adjustable fixation device;   identifying, from the plurality of adjustable length rigid struts, an adjustable length rigid strut most axially aligned with a treatment site on the bone based on the 3D model; and   determining said one or more tissue parameters based on a measurement signal of said one or more measurement signals, which measurement signal is associated with said adjustable length rigid strut most axially aligned with said treatment site.   
     
     
         20 . The method according to  claim 18 , wherein said one or more tissue parameters comprise a measure of ossification of tissue at said treatment site;
 wherein the method comprises:
 evaluating said measure of ossification; and 
 generating an indication as to whether bone tissue is sufficiently healthy to:
 initiate or resume bone repositioning; or 
 remove the adjustable bone fixation device.